TWI440665B - Bulk light diffuser composition - Google Patents

Description

Integral light diffuser composition Field of invention

This application is filed on October 5, 2006, the priority of the U.S. Provisional Application Serial No. 60/849,720.

The present invention is generally directed to a composition suitable for use in the fabrication of a polymeric display substrate, preferably a light diffusing polymeric display substrate. The composition comprises (a) a hydrogenated block copolymer, preferably a substantially fully hydrogenated block copolymer, more preferably a fully hydrogenated block copolymer, and (b) a particulate light diffusing material. .

Background of the invention

U.S. Patent No. 6,908,202 discloses an overall light diffuser material comprising from 95% to 99.8% by weight of polycarbonate, and vice versa from 0.2% to 5% by weight of particulates. The light diffusing material is based on the total weight of the polycarbonate and the light diffusing material. Thus, a film or sheet prepared from the overall light diffuser material has a thickness from 0.025 millimeters (mm) to 0.5 millimeters and at least 70% when tested in accordance with American Society for Testing and Materials (ASTM) standard D 1003. A percent transmittance (%) and a percent turbidity of at least 10%.

Polycarbonate has a use limit based on its known nature of absorbing moisture. In addition, polycarbonates have optical performance characteristics, such as transmittance, refractive index, and brightness in integrated light diffuser applications that are not desirable for certain commercial applications, especially when used with very short wavelengths (eg, near super purple External light range) or application of laser light with wavelengths up to approximately 440 nanometers (nm).

U.S. Patent No. 6,908,202 (column 1, lines 9-19) teaches that optical films or sheet materials are commonly used to guide, diffuse or polarize light in a backlit computer display or other display system. In backlit displays, the user of the display observes that certain films enhance the brightness of the light and allow a system incorporating the display to consume less power to produce a desired degree of coaxial illumination. Certain display systems, such as liquid crystal displays (LCDs), desirably include a diffusion composition to improve illumination uniformity.

U.S. Patent No. 6,815,475 discloses completely or substantially fully hydrogenated bulk copolymers such as hard hydrogenated block copolymers having greater than 90% hydrogenation of diene and greater than 95% aromatic hydrogen (or aromatic hydrocarbons such as styrene) hydrogenation. The materials, in each case, were based on a total of available double bonds or unsaturation in the bulk copolymer prior to hydrogenation. The hydrogenated block copolymer has an average molecular weight (Mn) of from 30,000 to 150,000, and may be three, multiple, push blocks or star block copolymers such as SBS, SBSBS, SIS, SISIS, and SISBS (where S It is made of polystyrene, B is polybutadiene, and I is polyisoprene. These copolymers are rumored to exhibit light transmission for visible wavelength light while having excellent physical properties at standard temperature and elevated temperature. According to column 2, lines 38-49, these properties include high glass transition temperature (T _g ), low water absorption, and good strength. However, U.S. Patent No. 6,815,475 does not define "high", "low" or "good".

However, U.S. Patent No. 6,815,475 defines "sheet" as having a thickness of 20 mils (0.51 mm) or more, and defines "film" as having There is a thickness of less than 20 mils (0.51 mm). These sheets can be used in a variety of applications requiring optical clarity, such as flat panel displays, liquid crystal displays, and rear projection television screens.

It is understood by those skilled in the art that, as determined in accordance with ASTM D1003, the percent total transmittance (%TT) and the percent haze (%H) represent a universal gauge of optical properties such as transparency and light diffusing properties of the material. Those skilled in the art also understand that ASTM D-570 is used for a determination of water absorption by immersing it in Chinese 74 degrees (°F) (23.3 degrees Celsius (°C)) for twenty-four (24) hours. Approved test.

U.S. Patent No. 6,451,924 includes a delay of less than 25 nm (less than 0.000042 birefringence) per 0.6 mm of substrate, and a high data density optical media disc having a water absorption of less than 0.05% as measured by ASTM D570. . The birefringence delay measurement involves placing a molded DVD disc substrate between the crossed polarizer and the quarter-wave plate (toward the opposite direction) and using the light generated by a 633 nm laser for the distance disc The injection port of the sheet was measured at 20 mm. Column 12, line 58 to column 13, line 8 indicates the theory of computational delay and birefringence. The disc substrate comprises a hydrogenated block copolymer, preferably a hard hydrogenated block copolymer, which is hydrogenated to a degree equal to that disclosed in the aforementioned U.S. Patent No. 6,815,475.

U.S. Patent No. 6,376,621 provides hydrogenated bulk copolymers of styrene and isoprene, and it is recommended to use such copolymers to prepare optical media discs having very low birefringence values. U.S. Patent No. 6,376,621 defines "birefringence" as double refraction, meaning that it is an optical distortion resulting from a difference in refractive index in a material through which visible light passes.

Optical media are disclosed in U.S. Patent No. 6,350,820, which teaches that the hydrogenated bulk copolymer is transmissive to light of visible wavelengths and exhibits excellent properties at both standard and elevated temperatures. These properties include high glass transition temperature ( _Tg ), low water absorption, elasticity, excellent melt processability, and surprisingly negligible birefringence. U.S. Patent No. 6,350,820 teaches the use of such copolymers to prepare optical media devices and components thereof, including a transparent substrate, a protective layer or an information layer.

Summary of invention

A first aspect of the present invention is an integral light diffuser material comprising from about 80% to about 99.9% by weight of a hard and substantially fully hydrogenated block copolymer, and conversely from a weight percent of 0.1 From wt% to 20% by weight of light-diffusing particles having a refractive index at least different from the refractive index of the bulk copolymer (greater than or equal to (≧)) 0.02 units, each weight percent by weight of hydrogenated bulk copolymer and light Based on the total weight of the diffusing particles, the bulk copolymer constitutes a continuous polymer phase, and the light diffusing particles constitute a dispersed phase in the continuous polymer phase; the bulk copolymer contains at least two different hydrogenated aromatics An ethylene polymer, and at least one hydrogenated diene polymer; the hydrogenated block copolymer further characterized by a water absorption of less than or equal to 0.1%, preferably ≦0.075%, and more preferably ≦0.05%, transmission Degree greater than (>) 90%, and a density of 0.92 to 0.95 grams per cubic centimeter (g/cc) whereby a two millimeter slab comprising the integral light diffuser material has a total percent transmittance of at least 50% ( %TT) and at least 70 % turbidity (%H) (ASTM D-1003).

The refractive index "n" of a material indicates the ratio of the velocity of light in a reference medium (typically a vacuum) to the velocity in the material. It is recognized by those skilled in the art that the refractive index is the ratio between the values of the same measurement unit, which is a unitless value. By showing that if the refractive index of the bulk copolymer matrix is 1.51, a refractive index of the light-diffusing particles which differs from the refractive index of the bulk copolymer matrix by 0.02 units can be less than or equal to (≦) 1.49 or ≧ 1.53.

A second aspect of the present invention is a backlight display device comprising a light source for generating light, and an optional light guide plate for guiding light along the same, comprising a reflective surface for reflecting light away from The light guide plate, and a film or sheet comprising the first aspect of the overall light diffuser material and capable of receiving light directly from the light source or indirectly from the light guide plate.

In addition to being used in a backlit display device, the integral light diffuser material of the present invention can be used to prepare a protective cover member for a transparent or light transmissive device, including but not limited to: A plasma screen, a liquid crystal display, a light emitting diode device, and a cathode ray tube display device.

As with the users of this specification, the definitions shown in the preceding paragraphs of this specification or elsewhere indicate the meaning of their initial definition.

When a range is mentioned herein, for example from 2 to 10, the ends of the range (2 and 10) are included within the range unless specifically excluded.

The overall light diffuser material of the present invention has a percent transmittance (%TT) of ≧50% (ASTM D-1003), preferably ≧60%, more preferably ≧65%, more Jiayi is 70%, better than 75%, and the best is 80%. These integral light diffuser materials also have a haze percentage (%H) of ≧70% (ASTM D-1003), preferably ≧80%, more preferably ≧85%, more preferably ≧90%, and the best ≧ 95%. One of the practical upper limits of the percentage of turbidity (%H) is 100%. It will be appreciated by those skilled in the art that a matrix material such as a hard and substantially fully hydrogenated bulk copolymer and a diffusion particle such as organic diffusion particles dispersed in the matrix material have a The difference in refractive index, so 100% of the TT value is quite difficult to obtain. These %TT and %H values are for a molded plate having a thickness of one of two (2) millimeters or extruded integral light diffuser material. Those skilled in the art will recognize that as the thickness of the plate increases, the %TT will decrease and the %H value will increase because the diffusion of particles as the length of the optical path through the sheet increases the light in the sheet. The scattering increases. However, for standard turbidity measurements, some instruments may display an indication value that exceeds 100%. In terms of a practical issue, those skilled in the art generally consider such values to be human factors in the design of the instrument and treat such higher numbers as equivalent to 100%.

As disclosed in U.S. Patent No. 6,908,202, the entire disclosure of which is incorporated herein by reference in its entirety, in particular in the col. . The choice of light diffusing particles is related to obtaining a desired refractive index for one of the hard and substantially fully hydrogenated bulk copolymers and for producing any physical properties required in the hard and substantially fully hydrogenated bulk copolymer. The balance between significant counter effects is minimized. Examples of suitable light diffusing organic materials include polystyrene, poly(acrylate), poly(alkyl methacrylate) Ester), such as poly(methyl methacrylate) (PMMA), poly(tetrafluoroethylene) (PTEE), decane, such as hydrolyzed poly(alkyltrialkoxides) and polymethylsesquioxanes And a mixture comprising at least one of the above organic materials, wherein the alkyl group has from 1 to 12 carbon atoms. In the selection of an organic light diffusing particle, an additional consideration in maintaining the particular integrity of the light diffusing particle is the selection of a material in a diffuser plate dominated by a hard and substantially fully hydrogenated bulk copolymer. It is resistant to deformation during its manufacture or processing to its final shape. For polymeric light-diffusing particles, this can be achieved by selecting a material that does not produce a substantial dimensional change at the temperature (e.g., 250 ° C) used to melt the hard and substantially fully hydrogenated bulk copolymer. In particular, particles that are interactively joined prior to addition to the bulk copolymer matrix material are selected. Examples of suitable light-diffusing inorganic materials include materials containing talc, calcium carbonate, barium, decane, titanium, zirconium, hafnium and zinc, such as oxides or sulfides of the above, such as vermiculite, zinc oxide, oxidation And a mixture comprising at least one of the above inorganic materials. The inorganic material can also be treated with an organic coating if desired.

The choice of light diffusing particles depends, at least in part, on the difference in refractive index between the particles and the substantially fully hydrogenated bulk copolymer matrix. In order to provide sufficient diffusion properties, preferably simultaneous synchronization limitations, and more preferably to eliminate light propagation attenuation, as described above, the refractive index of the diffusion particles must differ from the refractive index of the copolymer matrix by 0.02 units, preferably ≧ 0.03 units. And more preferably 单位0.05 units. Further, it is desirable that the diffusion particles have an average or intermediate diameter ranging from 0.1 μm to 100 μm, and the range is preferably from 0.1 μm to 50. Micron, and more preferably from 0.1 micron to 20 microns. Those skilled in the art will recognize that a particular batch of diffusing particles will produce a change in particle size. Depending on how the diffusion particles are made, the particle size may vary, for example, like any single form distribution (single distribution spikes, such as a Gaussian distribution or a Poisson distribution), a double form distribution (two Distribution spikes, a multiple form distribution (three or more distribution peaks). In each case, the distribution of the particle size in a particular batch of diffusion particles to the total number of particles is shown in a two-dimensional plot.

A hard and substantially fully hydrogenated block copolymer suitable for use in the overall light diffuser material of the present invention is suitably prepared in accordance with U.S. Patent No. 6,632,890, the disclosure of which is incorporated herein by reference. The bulk copolymer preferably comprises at least two different hydrogenated polymerized vinyl aromatic monomers (e.g., styrene, vinyl toluene, alpha-methylstyrene, or t-butylstyrene) and at least one hydrogenated group. Polymerized conjugated diene monomer (eg 1,3-butadiene, 2-methyl-1,3-butadiene, 2-methyl-1,3-pentadiene and/or isoprene) Alkenes alternate. Those skilled in the art can immediately replace the above with a styrenic monomer or a diene monomer. These bulk copolymers have a total number average molecular weight (Mn _t ) of from 30,000 to 120,000, wherein each hydrogenated vinyl aromatic monomer polymer block (A) has a number average molecular weight of from 5,000 to 50,000 (Mn _a And each hydrogenated conjugated diene polymer block has a number average molecular weight (Mn _b ) of from 4,000 to 110,000. U.S. Patent No. 6,632,890 also discloses having from Mn _t 30,000 to 200,000, the Mn of from 10,000 to 100,000 _A, and (pentablock) copolymer from the hydrogenation of five Mn _b of from 2,000 to 50,000. For the lead (unhydrogenated) block copolymer, gel permeation chromatography (GPC) was used to determine the molecular weight value relative to the homopolymer standard.

Both U.S. Patent No. 6,632,890 and U.S. Patent No. 6,815,475, the entireties of each of each of each of each of , multi-block copolymers, push-block copolymers, and star-shaped block copolymers, such as SBS, SBSBS, SIS, SISIS, and SISBS (where S is polystyrene, B is polybutadiene, and I is Polyisoprene). The bulk copolymers comprise at least one of three blocks, but can also include any number of additional blocks, wherein the blocks can be attached to the backbone of the three polymers at any location.

U.S. Patent No. 6,350,820, the entire disclosure of which is incorporated herein by reference in its entirety in the entire entire entire entire entire entire entire entire entire entire entire entire entire entire portion The microphase separation is exhibited on the polymerized segments which are different in composition or in composition. U.S. Patent No. 6,350,820 teaches that the microphase separation occurs due to the incompatibility of the polymeric segments in the bulk copolymer, and it is suggested that the separation of the bulk segments can be detected by having different glass transition temperatures.

U.S. Patent No. 6,350,820 defines "hard hydrogenated block copolymer" as "hydrogenated conjugated diene polymer block" in columns 1 through 12 of column 3 having 40:60 to 5 for hydrogenated vinyl aromatic polymer blocks: The weight ratio of 95 is preferably 35:65 to 10:90, more preferably 30:70 to 15:85, and the total weight of the hydrogenated conjugated diene polymer block and the hydrogenated vinyl aromatic polymer block is Benchmark." U.S. Patent No. 6,350,820 teaches that the hydrogenated vinyl aromatic polymer block and the hydrogenated conjugated diene polymer block are typically the total weight of the hydrogenated copolymer. At least 80 percent, preferably at least 90 percent, and more preferably at least 95 percent of the total weight of the article.

The preparation of bulk copolymers is detailed in U.S. Patent No. 6,350,820, the entire disclosure of which is incorporated herein by reference. In general, the preparation is carried out by anionic polymerization using a reaction such as a second butyllithium or one of n-butyllithium carbocation initiators with an anionic polymerizable monomer, the growing polymer The chain is interrupted by a cation or by coupling using a divalent coupling agent such as 1,2-dibromoethane, dichlorodimethyloxane or phenyl benzoate. Anionic polymerization can also be initiated by the reaction of an anionic polymerizable monomer with a double acting anionic initiator such as 1,3-bis(1-phenethyl)benzene, which is as U.S. Patent No. 4,200,718, and U.S. Patent No. 4,196,154, the disclosure of which is incorporated herein by reference.

U.S. Patent No. 6,350,820 discusses the procedure for hydrogenating bulk copolymers in column 4, line 52 to column 8, line 23. All of the teachings of U.S. Patent No. 6,350,820, which is incorporated herein by reference in its entirety, is incorporated herein by reference. In general, hydrogenation removes the point of unsaturation in both the polymerized diene monomer block and the polymerized styrenic monomer block, and uses a hydrogenation catalyst, such as an inorganic matrix-supported metal catalyst (eg, Palladium (Pd) on barium sulphate in U.S. Patent No. 5,352,744 or nickel (Ni) on diatomaceous earth as in U.S. Patent No. 5,352,744. The hydrogenation can also be carried out using hydrogen as well as those disclosed in U.S. Patent No. 5,352,744, U.S. Patent No. 5,612,422, and U.S. Patent No. 5,645,253. Heterogeneous catalysts occur. The heterogeneous catalyst can comprise a metal microcrystal supported by a porous oxyalkylene group, wherein the metal is an eighth group (as described in the CRC Handbook of Chemistry and Physics, 77th Edition (1996-1997)" The periodic table of elements shown is a metal such as nickel, cobalt, rhodium, palladium or platinum.

Although not within the scope of the present invention, the catalyst support and the preparation of the catalyst are described in detail in column 6, line 30 to column 7, line 21 of U.S. Patent No. 6,350,820. The doctrines of the various reference methods described in this paragraph, the previous paragraph or the subsequent paragraphs are hereby incorporated by reference in their entirety.

The hard and substantially fully hydrogenated block copolymer exhibits optical clarity ranging from 0.1 mm to 50 mm. The conversion of the hard and substantially fully hydrogenated block copolymer of the present invention into a film, sheet or other manufacturing shape is preferably produced by using conventional procedures such as injection molding, sheet forming, sheet extrusion. If desired, the pattern can be embossed or embossed on the exterior surfaces of such films, sheets or other fabricated shapes to facilitate or improve optical properties (e.g., light diffusing ability), or as aesthetics or both. In addition, the external surfaces can be modified by conventional procedures, one of which is to apply a coating to enhance or modify the barrier, adhesion, optical or other functional properties of such films, sheets or other fabricated shapes.

The preparation of a diffuser panel for use in a liquid crystal display (LCD) requires consideration of dimensional changes that may occur during use of the panel to ensure that the diffuser panel remains substantially in its original position in the device during use. Dimensional changes may be due to thermal expansion of the polymer's overall light diffuser material, or by Produced by interactions in environments such as moisture absorption.

The estimate of the dimensional change of the diffuser plate is derived from the description of the relationship between an edge gap formed between a diffuser plate or sheet and an edge of a cabinet that houses the diffuser plate. The equation for the estimation of the edge gap is as follows: Gap (gap) = 0.7 (mm) + [L (T _{2 -} T ₁ ) CTE] + (LW ₂ )

In the equation, 0.7 mm is a constant indicating machine tolerance or allowable variability of part size; T ₁ means temperature before use (degrees Celsius or ° C), typically room temperature (typically 25 ° C); T ₂ represents the highest operating or operating temperature (in °C); L is the diffuser plate length (in millimeters); CTE is the linear thermal expansion coefficient of the polymeric matrix (in micrometers per meter Celsius (μm / M ° C) And W _a is equal to the weight percentage of water vapor absorption based on ASTM D-570. For the edge gap estimate, consider a constant for the CTE system used to polymerize one of the polymers. In other words, each polymer can be considered to have a unique CTE.

Manufacturers of LCD device comprising a desired diffuser plate (which occurs when the device changes from the ambient temperature to the operating temperature (e.g., T ₂₎ time) during heating with a slight dimensional change or expansion as possible. For an LCD panel with a diagonal length of 32 inches (813 mm), a practical maximum expansion or gap is in the range from 2.5 mm to 8 mm. Although manufacturers may allow the use of an integrated light diffuser material with low moisture absorption, such LCD panels do not exceed the maximum practical expansion, manufacturers are optimistic about reducing or even eliminating moisture uptake.

The overall light diffuser material of the present invention is dominated by a hard and substantially fully hydrogenated bulk copolymer having a very low water vapor absorption as described above, for example, 0.1% according to ASTM D570. Preferably, it is 0.075%, and more preferably 0.05%. By contrast, for the manufacture of polycarbonate overall light diffuser material of PC-based (PC) of a material having a high absorption of water vapor, e.g. Calibre ^TM 303 (Doyle (Dow) Chemical Company, density It is 0.1 gram per cubic centimeter (g/cc) and is 0.15%. Polymethyl methacrylate (PMMA) resin having a moisture absorption than a PC, for example, Plexiglas ^TM DR-101 (Altuglas International, Inc.) in terms of 0.40%.

The overall light diffuser material of the present invention also has a CTE, and when factored into the gap equation described above, it is possible to manufacture a 32 inch (813 mm diagonal measuring length) LCD panel that does not expand beyond 8 mm. .

The CTE, water vapor absorption, and calculated gap equation values for a monolithic polymer of light diffuser material suitable for making a 32 inch (813 mm) LCD panel are as follows: Example (Ex) 1~ A substantially fully hydrogenated bulk copolymer of 4 - CTE = 148 microns / meter Celsius (μm / M ° C), water vapor absorption = 0.05%, and the gap equation value is 7.1 mm; PC (Calibre ^TM 303) - CTE = 59 μm / M ° C, water vapor absorption = 0.16%, and the gap equation value is 4.3 mm; and PMMA (Plexiglas ^TM DR-101) (according to TA Ossward and G. Manges) In "The Science of Polymer Materials Used by Engineers", TAOssward and G. Menges, described in the 1996 edition of Munich Hanser Press) - CTE = 70 μm / M ° C, water vapor absorption = 0.4%, and the gap equation value is 6.8 mm .

Detailed description of the preferred embodiment Analysis program

The specific gravity (g/cm ³ ) is determined in terms of the number of grams per cubic centimeter of the displacement as specified by ASTM Test Method D792.

For Examples 1 to 4 and Comparative Examples A to I, a turbidimeter with a 12 volt (V) halogen light source (turbidity meter model NDH 300A, manufactured by Nippon Denshoku Co., Japan) was used to measure % according to ASTM D-1003. TT and % turbidity (Haze). "Haze" is defined as the percentage of diffuse light transmission that is more than 2.5 degrees from the angle of incidence for total light transmission.

For all other examples, the use a Haze-Gard Plus ^TM haze meter (BYK Garder Co.) substituted Model NDH 300A haze meter.

ASTM D-1003 recommends that we use a bidirectional scattering distribution function (BSDF) in accordance with ASTM E-2387-05 for materials with a turbidity of more than 30%. However, those skilled in the art will understand that only a few people will use BSDF measurements because they do not provide a quick comparison between different materials. Conversely, it has been found that one of the instruments such as the Haze-Gard Plus turbidity meter determines % turbidity and %TT has broad acceptance and even for high diffusion such as polymeric films and polymeric sheets (% turbidity over 30%) The translucent material can also provide a consistent data set.

Use a quartz glass dilatometer to operate at a heating rate of 10 ° C (° C / min) per minute from one of -30 ° F (-34 ° C) to 30 ° F (-1 ° C) to determine compliance with ASTM D696-98 The linear thermal expansion coefficient (CTE) of the temperature range.

The following examples show, but are not limiting, the invention, unless otherwise stated Parts and percentages are based on weight and all temperature units are °C. The example (Ex) of the present invention is represented by Arabic numerals, and the comparative example (Comp Ex) is represented by uppercase letters. Unless otherwise stated, the "room temperature" and "circumference temperature" in the text are commonly known as 25 °C.

Examples 1~4 and Comparative Examples A~B

A hard and substantially fully hydrogenated block copolymer using a twin screw extruder (Werner Pfleider, WMP ZSK-25, length to diameter ratio (L/D) of 42 and one screw of 25 mm diameter) Conversion to a matrix polymer, and for Examples 1-4 and Comparative Example B (excluding Comparative Example A without diffusion particles), one quantity (Comparative Example B and Examples 2, 3, and 4 are 2%) The weight percent wt%, and Example 1 is 3 percent by weight of the diffusing particles enter a polymer melt of Comparative Example A, or enter a polymer melt of Comparative Example B and Examples 1-4. In the body compound. In the polymer melt compound, the diffusing particles from the dispersed phase and the hard and substantially fully hydrogenated bulk copolymer form a continuous phase. The twin screw extruder has six barrel sections with 180 ° C, 220 ° C, 230 ° C, 240 ° C, 245 ° C and 245 ° C and a stamp temperature of 245 ° C. The polymer melt or polymer melt compound exiting the extruder has a melt temperature of about 250 °C. The polymer melt or polymer melt compound, where appropriate, is converted to a polymer or polymer compound bead using an underwater granulator. The polymer or polymer compound bead is sent to an injection molding apparatus (Creator Model CI-100 injection molding apparatus) for converting the polymer to have a millimeter (mm) as shown in Table 1 below. A sheet or plate of thickness of two millimeters or three millimeters. As indicated in this paragraph Each wt% is based on the combined weight of the hard and substantially fully hydrogenated block copolymer and diffusion particles.

The hard and substantially fully hydrogenated block copolymer (an experimental copolymer prepared by Dow Chemical Company) forms a SBSBS pentablock copolymer having 60,000 total copolymer Mn and 85 wt% benzene prior to hydrogenation. The ethylene (S) content and the 15 wt% butadiene (B) content are based on the total polymer weight before hydrogenation in each case; and when considered together (total is 100 wt%), the butadiene content comprises 90% by weight of 1,4-butadiene and 10% by weight of 1,2-butadiene, in each case based on the weight of the total butadiene block, and the sum is 100% by weight; having 0.95 grams per cubic centimeter ( a density of g/cc or g/cm ³ ); a glass transition temperature (T _g ) of 132 ° C; a percentage of water absorption of less than 0.05% (ASTM D570); and a degree of hydrogenation of 99.5% of styrene, The percentage of total styrene before hydrogenation is used as a benchmark. The hard and substantially fully hydrogenated block copolymer has a nominal refractive index of 1.51.

Use an ARES galvanometer (manufactured by Texas Instruments) equipped with an automatic strain adjustment to maintain the measured torque between 200 gram-cm and 900 gram-cm, a one-frequency oscillator per second, 0.1% The initial strain, the temperature range from -100 ° C to 160 ° C, and the rate of temperature rise of 3 ° C per minute are formed by a solid rectangular rod (expanded by the copolymer at a temperature of 250 ° C and having The dynamic mechanical analysis of a length of 45 mm, a width of 12.5 mm, and a thickness of 3.2 mm) determined the _{Tg of} the hard and substantially fully hydrogenated bulk copolymer. The loss factor (tan δ) spike temperature obtained by this dynamic mechanical analysis is defined as the T _{g of} the hard and substantially fully hydrogenated bulk copolymer.

The diffusion particles can be organic (Comparative Example B and Examples 1-3) or inorganic (Example 4). The organic particles used in Comparative Example B were cross-linked, monodisperse acrylic particles having an average particle size of 5 micrometers (μm), a density of 1.19 grams per cubic centimeter (g/cm ³ ), and a refractive index of 1.49. , and the coefficient of variation or CV value was 9% (commercially sold by Soken chemical Co., Ltd. and Engineering, trade name CHEMISNOW ^TM MX-500). The organic particles used in Example 3 are cross-linked, monodisperse acrylic particles having an average particle size of 10 microns, a density of 1.19 grams per cubic centimeter, a refractive index of 1.49, and a coefficient of variation or CV of 9 (The market is sold by Soken Chemical and Engineering Co., Ltd. under the trade name CHEMISNOW ^TM MX-10). The organic particles used in Examples 1 to 2 are interconnected polystyrene (PS) particles having an average particle size of 10 microns, a density of 1.09 g/cm3, and a refractive index of 1.59 (marketed by Soken chemical & Engineering Co., sold under the trade name CHEMISNOW ^TM SGP-50C). The inorganic particles used in Example 4 were calcium carbonate (CaCO ₃ ) particles having an average particle size of 4.6 μm (particle size ranging from 0.5 μm to 10 μm) (marketed by An Tai Micron Industrial Co., Ltd.) ).

The % turbidity and % TT of the sheet or panel were estimated according to the above procedure, and the summary estimation results are summarized in Table I below.

Comparative example C~E

Copy Examples 1 to 4 and Comparative Examples A ~ B of the program, it will be changed into a polymer matrix of polycarbonate (PC) resin (CALIBRE ^TM 201-15, Dow Chemical Company), and a melting temperature of 280 deg.] C Extruded PC (Comparative Example C) or a PC compound (Comparative Examples D~E). Comparative Example C is a pure PC resin and does not contain light diffusing particles. Comparative Example D contained 2 wt% calcium carbonate (CaCO ₃ ); and Comparative Example E contained 2 wt% MX-10 particles. The % turbidity and %TT of the resulting panels were evaluated in the same manner as in Examples 1 to 4 and Comparative Examples A to B, and the summary evaluation results are summarized in Table I below.

The data in Table I shows that although a pure and substantially fully hydrogenated block copolymer (Comparative Example A) and a neat PC resin (Comparative Example C) are similar, they are unsatisfactory due to the absence of diffusion particles (% H)), and has similar properties when loaded with calcium carbonate as an inorganic diffusion particle (Example 4 vs. Comparative Example D), whereas when the diffusion particle is a MX-10 cross-linked acrylic material (Example 3) For the organic materials of Comparative Example E), the measured properties are clearly different. The cross-linking acrylic particle size was halved from 10 microns of Example 3 to 5 microns of Comparative Example B with little effect on %TT, but had a significant effect on %H. Take Calcium carbonate as both inorganic diffusion particles and certain organic diffusion particles (eg, cross-linked PS particles) are in some plate thickness (eg, 1 mm for calcium carbonate (Comparative Example C and Example 4), for 2 wt% of cross-linked PS The granules (Example 1) are 1 mm and 2 mm, and for 3 wt% of the cross-linked PS particles (Example 2) of 1 mm, 2 mm and 3 mm), satisfactory %H and %TT values are produced (two All are greater than 70%). In other words, the information shown in Table I is reminiscent of the ability to add a plurality of light-diffusing particles comprising a substantially fully hydrogenated block copolymer from a dispersed phase to a continuous or matrix phase ( The desired combination of optical properties, such as turbidity and transparency, is obtained whether polymeric or inorganic.

Comparative example F~J

The %H and %TT of five commercially available diffuser plates having a thickness of 2 mm were evaluated in the same manner as in Examples 1 to 4 and Comparative Examples A to B, and the results are summarized in Table II below. All data represent the average of the five measurements, and the accuracy of each measurement is within plus or minus three units. Comparative Example F (marketed by Tsutsunaka Plastics Industries, Inc. under the trademark SUNLOID ^(TM )) is a polycarbonate (PC) matrix in which proprietary diffusion particles are interspersed. Comparative Example G (obtained by disassembling a Sony (SONY) liquid crystal display (LCD) television set) comprises a gold-olefin catalytic cyclic olefin copolymer (mCOC) matrix in which unknown diffusion particles are interspersed. Comparative Example H (marketed by Asahi Chemical Company) is a PMMA matrix in which polystyrene (PS) diffusion particles are interspersed. Comparative Example I (marketed by Mitsubishi Chemical Company and recently introduced into the LCD market) is also a PMMA matrix with PS diffusion particles interspersed. Comparative Example J (sold commercially by the Entier Technologies Co., Ltd. under the trademark ENTIER ^TM EMS) system is a styrene - maleic anhydride (SMA) resins, interspersed with polypropylene (PP) diffusing particles.

The data in Table II represents the %H and % total transmission values for a range of commercially available diffuser panels and provides a reference for comparison with diffuser panels prepared using the integrated light diffuser materials of the present invention. .

The results of a comparison of the 2 mm thick diffuser plate data in Table I with the data in Table II are reminiscent of the composition of the present invention (especially the compositions of Examples 1-3, and comparative examples thereof). The composition of F~J has a significantly higher %TT value than the one in the preparation of the diffuser plate. Those skilled in the art will recognize that, for example, between two %TT values, a higher %TT value tends to provide a display device component (such as a diffuser plate) and other light processing applications. Higher light utilization efficiency.

Example 5~8

Copy examples 1~4 and comparative examples A~B, but use different amounts of an interactive polystyrene material (SBX-8 from Seikisui Plastic Co., Ltd., Japan, with an average particle size of 8 microns and a refractive index of 1.59) The diffusion particles used in Examples 1 to 4 and Comparative Examples A to B were replaced as a diffusion material, and the extruder was changed to an 18 mm Liestritz twin screw extruder. The amount of the diffusion material was 2 wt%, 1.5 wt%, 1 wt%, and 0.5 wt%, respectively, and each case was based on the mixed weight of the substantially fully hydrogenated bulk copolymer and the diffusion material. Instead of the injection molding as in Examples 1 to 4, the extruded molding sheets had the thicknesses shown in Table IV below. The dried polymer compound beads were placed in a vacuum oven operating at a set point temperature of 110 °C for two hours prior to extrusion molding. Extrusion molding means compound dried polymer beads are placed in a TETRAHEDRON ^TM label (as sold by the San Diego, California, Tetrahedron Associates, Inc.) using a mold temperature set point of 250 deg.] C, and A pressure of 150 pounds per square inch (150 psi, 1.03 million Bass (MPa)) was applied. The %H and %TT data are summarized in Table III below.

The data in Table III shows that we can change the amount of a diffusion particle having a refractive index that differs from the refractive index of the substantially fully hydrogenated bulk copolymer by at least 0.02 (in this case 0.08). Modify the optical properties (%H and %TT). With at least one percent by weight (1 wt%) (Example 7), we are able to achieve a substantially complete diffusion in a 1.2 mm thick sample or a 1.8 mm thick sample while maintaining at least 80% %TT.

Example 9~10

Copy Example 7 (1 wt% diffusion particle content), but change the size of the diffusion particle to 6 μm in Example 9 (SBX-6 from Seikisui Plastic Co., Ltd., Japan), and change it to 12 μm in Example 10 (Japan Seikisui Plastic Co., Ltd.) Produced by SBX-12). Examples 9 and 10 of the %H and %TT lines are summarized in Table IV below.

The data in Table IV shows that the diffusion particle size affects the percent turbidity (%H) and has some effect on %TT. Based on this data, as the size of the diffusion particles increases, %H increases in an inverse relationship to the size of the diffusion particles, while %TT shows a slight increase, at least in 1.2 mm thick plates. Therefore, we can modify the required optical properties (%H and some degree of %TT) by changing the size of the diffusion particles.

Example 11~12

Copy examples 5-8, but change the type and amount of diffused particles. Example 11 uses a 5% cross-linking poly(methylmethacrylate-co-etylene glyeol dimethacrylate) polymer (PMMA) (Sigma-Aldrich, Lot No. 11005PC) The average particle size is 7 microns and the refractive index is 1.49). Example 12 used the same 2 wt% diffusion particles as in Example 16 and a 0.5 wt% cross-linked polystyrene polymer (Example 8) mixture. The %H and %TT systems of Example 8, Example 11 and Example 12 are summarized in Table V below.

The data in Table V shows that although an interactively linked polystyrene or an interlinked PMMA diffusion particle itself is capable of producing satisfactory optical properties (%H and %TT), the mixing of the two can even provide more Good result. The data in the table is reminiscent of the opportunity to make further modifications to the combination required to select one of the optical properties by changing the type and amount of diffusing particles.

Example 13~18

The above examples 5 to 10 were reproduced, but 2 mm and 3 mm plates were prepared by injection molding as in the previous examples 1 to 4. Examples 13 to 18 contain diffusion particles of the same type as Examples 5 to 10, but differ in number. The %H and %TT lines are summarized in Table VI below.

Comparing the optical properties of the panels used as the diffuser panels for the flat panel displays in Table II (Comparative Examples E~I), the data shown in Table VI shows the panels (thickness) manufactured by Examples 13-18. 2 mm), except for example 16 It has a very high turbidity and is able to provide almost complete light diffusion (that is to say %H > 99%) and at the same time can have a very high percentage of light transmission of at least 80%. Both optical properties show significant improvements and benefits for exposing the invention to use as an integral light diffuser application.

The %H and %TT of the 2 mm thick sheet prepared by injection molding (Table VI) are almost equal to the material having a slightly smaller thickness but prepared by extrusion molding. It is so reminiscent that the manufacturing method has a slight influence on the diffusion board optical trade (if any). For 1.2 mm thick plates (Tables III and IV), the %H and %TT data are further reminiscent of the fact that the compositions of the present invention can be used to make integral light diffuser panels, and Comparative Example F The commercially available diffuser plates indicated in ~J have a substantially smaller thickness than the commercially available diffuser plates. For materials used by the overall light diffuser manufacturer, a small thickness can then result in cost savings.

For other substantially fully hydrogenated block copolymers and mixtures of such substantially fully hydrogenated block copolymers with a substantially complete argonized polystyrene and various diffusion particles or diffusion particles (all materials are as described above) ), similar results can be expected. In particular, an integral light diffuser composition based on a polymer block copolymer matrix is contemplated to provide a useful integral light diffuser matrix formed from a bulk copolymer. It has a polymerized styrene content of from 40% by weight to 95% by weight (based on the weight of the bulk copolymer) prior to hydrogenation. Likewise, modified substantially fully hydrogenated block copolymers due to the addition of types or customary additives are also expected to provide utility in this application, which protects substantially fully hydrogenated bulk copolymers. The material is protected from one or more thermal oxidations and decays due to exposure to ultra-ultraviolet light. We can further modify the overall light diffuser composition by adding a small amount of other additives (such as a fluorescent bleach) to modify the optical brightness and chroma of the diffuser film or sheet. We can also add processing aids or low molecular weight diluents to modify the properties of a substantially fully hydrogenated block copolymer or a mixture thereof with a substantially fully hydrogenated polystyrene homopolymer without departing from the invention. The spirit or scope. In addition, one can coat the surface of an integral light diffuser substrate with a coating to enhance physical or chemical attack, or to modify optical properties, without departing from the spirit or scope of the invention. We are also able to mold a sheet or sheet in a textured module, or to cast a film or sheet on an embossing roll to achieve a textured surface so that the surface roughness of an integral light diffuser article can be modified A further modification of the optical properties was achieved.

Claims (13)

An integral light diffuser material comprising from 80% by weight to 99.9% by weight of a hard and substantially fully hydrogenated block copolymer, and from 0.1% by weight to 20% by weight of light diffusing particles, One of the refractive index systems differs from the refractive index of the hydrogenated bulk copolymer by greater than or equal to 0.02, and wherein the light diffusing particles have an average particle size of ≧0.5 microns and are an alternating polymerized particle; each weight percentage is Based on the total weight of the hydrogenated bulk copolymer and the light diffusing particles; the bulk copolymer constitutes a continuous polymer phase, and the light diffusing particles constitute a dispersed phase in the continuous polymer phase; the bulk copolymer comprises At least two different hydrogenated vinyl aromatic polymers, and at least one hydrogenated conjugated diene polymer, whereby a two millimeter thick sheet comprising the integral light diffuser material has a total percent transmittance of at least 75% And a percentage of turbidity of at least 70% (ASTM D-1003). The overall light diffuser material of claim 1, wherein the total percent transmittance is at least 80 percent. The integral light diffuser material of any one of clauses 1 to 2, wherein the percentage of turbidity is at least 80 percent. An integral light diffuser material according to claim 3, wherein the percentage of turbidity is less than or equal to 100%. The integral light diffuser material of claim 1, wherein the substantially fully hydrogenated bulk copolymer comprises alternating styrene polymers and conjugated diene polymer blocks. An integral light diffuser material according to claim 5, wherein the substantially completely hydrogenated bulk copolymer is a hydrogenated styrene-isoprene-styrene block copolymer, a hydrogenated styrene-isoprene Diene-styrene-isoprene bulk copolymer, hydrogenated styrene-isoprene-styrene-isoprene-styrene block copolymer, monohydrogenated styrene-butadiene-benzene Ethylene block copolymer, monohydrogenated styrene-butadiene-styrene-butadiene block copolymer, monohydrogenated styrene-butadiene-styrene-butadiene-styrene block copolymer, At least one of a hydrogenated styrene-butadiene-styrene-isoprene block copolymer and a hydrogenated styrene-butadiene-styrene-isoprene-styrene block copolymer. A polymeric film comprising an integral light diffuser material according to any one of claims 1 to 6 wherein the film has a thickness of less than 20 mils (0.5 mm). A polymeric sheet comprising an integral light diffuser material according to any one of claims 1 to 6 wherein the sheet has a thickness of at least 20 mils (0.5 mm). The integral light diffuser material of claim 1, wherein the light diffusing particles have a refractive index that differs from a refractive index of the hydrogenated bulk copolymer matrix by greater than or equal to 0.03. The integral light diffuser material of claim 9, wherein the light diffusing particles have a refractive index that differs from a refractive index of the hydrogenated bulk copolymer matrix by greater than or equal to 0.05. Such as the integral light diffuser material of claim 1 of the patent scope, wherein the optical expansion The bulk particle size is an average particle size ranging from 0.5 microns to 100 microns. An integral light diffuser material as in claim 11 wherein the range is from 0.5 microns to 20 microns. A backlight display device comprising a light source for generating light; an optional light guide plate for guiding light along the light guide plate, the light guide plate comprising a reflective surface for reflecting light away from the light guide plate; and a film Or a sheet comprising the integral light diffuser material of claim 1 and receiving light directly from the light source or indirectly from the light guide.